## 1987 Vol. 11, No. 5

Display Method: |

**Abstract:**

It is described that the function,structure, amplitude characteristics and results of cosmic ray test of a prototype of the central drift chamber for Beijing Spectrometer (BES). It was found that if appropriate high voltage is applied on the field wires homogeneous signal amplitude from different Layer of the chamber can be obtained. The drift velocity deduced by track reconstruction is 5.3cm/μs. The spatial resolution is about 134μm.

**Abstract:**

Based on the basic principle of the function of the parrallel plate spark chamber, two formulae relating the clearing field to the detection efficiency and sentive time are derived. The validity of these formulae are tested by experiment and shown that they are useful in the choice of the clearing field properly for experiments.

**Abstract:**

This paper describes a position sensitive multiwire proportional chamber with effective area of 200×200mm

^{2}. The chamber combining with multi-layer lead γ-ray converter form a high density multiwire proportional chamber γ-ray detector. The lead converter is made in auniformly arranged matrix of 0.9mm diameter holes on a 1.1mm pitch. For 511keV photons the detection efficiency is 5.6%, and the spatial resolution is 1mm. The detector has been used in the investigation of positron camera, it also offers possibility for X-ray detection.

**Abstract:**

In this paper I summarize some results obtained from analyses of hadronic final state events. The analyzed data sample comes from Mark-J collaboration and covers an energy range from √S=12GeV to √S =46.78GeV. The integrated luminosity is 128.06Pb

^{－1}. We can search for production of open top quarks and toponium by measuring the total hadronic crossection R

_{h}

*.*Γ

_{ee}≤3.00keV(95% C.L.).

**Abstract:**

The kinematical analysis of the ring-like event observed in mountain emulsion chamber shows that this kind of events might relate to the multi-particle production within a narrow rapidity interval of the fragmentation region in the superhigh energy interactions, therefore possibly relate to the phase transition in the nucleus-nucleus interaction. The air cascade showers induced by superhigh energy nucleus-nucleus interactions are simulated by a transition model. Under the condition of the emulsion chamber experiment, the ring-like event is obtained.

**Abstract:**

In order to avoid unnecessary or unallowable exposure in the gamma-neutron mixed field, the radioactive-contact person should know the radiation environment at any time by himself when he is working. A new kind of pocket radiation doserate monitor (chirper) based on silicon PIN photodiode as detector is designed. It can be used to monitor the gamma doserate in the order of 1 mrem/h and the neutron doserate in the order of 10 mrem/h simultaneously. In this paper, the detector selection, the circuit design, the construction and the performance of the chirper prototype are described.

**Abstract:**

This paper is devoted to a study of the heterotic string action described by a (p,q)-type supersymmetric σ-model involving a two-rank antisymmetric tensor field (Wess-Zumino-Witten term). We discussed a certain quantization procedure of W-Z-W term and its impact on heterotic string by using the locally product structure of internal compact space.

**Abstract:**

In terms of the modified Sturm-Liouville theorem, the properties of the solutions to the Klein-Gordon equations with the potential tails is discussed and the corresponding Levinson's theorem is proved in this paper.

**Abstract:**

Using the parabolic Fermi distribution of the nucleon number density instead of the average density, a new method of computing the effective color dielectric constant and the nucleon bag radius in nuclei is presented, so that the physical picture is made more realistic, and the results thus obtained are better consistent with the data and have two new features.

**Abstract:**

This article treats the interacting Boson model (IBM-1) by the embeding theory of Lie subalgebra. From the considerations of stantard A

_{1}subagbra and the index relation of the embedding theory, we can get all the subagbra chains of IBM-1 model and prove that they exhaust the possible physically meaningful chains.

The Boson creation and annihilation operators are taken as basis for the realization of the embedding. In selecting the basis, angular momentum consideration is very crucial for the outcome of the correct physical result which has angular momentum as a good quantum number. Our results coincides with the original resul of Arima and Iachello.

**Abstract:**

In this paper, some decomposotion formulas of γ-type matrices are derived based on Gordon identities. As an illustration of the application of these formulas, the one gluon exchange potential between quark and antiquark is rederived which appears to be different from that obtained by Faessler, et al. As another illustration, the correct reduction of the γ-matrices appearing in the kernel function of Bethe-Salpeter equation for quark-antiquark system is achieved and yields an expression different from that derived by Mitre whose calculation was grounded on a wrong decomposition formula for one γ-type matrix.

**Abstract:**

The energy reponse in the effective solid angles and the spatial distribution of the detection efficiency for the four frequently used

^{8}Be detection systems are obtained by two methods: Monte Carlo simulation and integration of the distribution function. The agreement of the results by the two methods is good. The resultes are tested are tested by some measurements with different geometry and compared with the published data.

**Abstract:**

Excitation functions and angular distributions of the residual nuclei I and Sb were measured in the reaction of

^{12}C on

^{115}In at energies up to 72MeV using radiochemical techniques. A kinematic analysis of the angular distributions showed probable mechanisms leading to productions of I and Sb isotopes.

**Abstract:**

The oscillatory structure appeared in the differential cross section of the reaction for

^{16}O(

^{16}O,

^{12}C)

^{20}Ne may be explained by particle transfer from covalent channel to ionic channel in the nuclear molecular orbital theory.

**Abstract:**

A simple model by which the mass drift can be expected in heavy ion reaction is suggested. The drift of average value of mass distribution with increasing dissipation energy is very small, because large damping effect hinders the driving potential in the process of energy equilibration while in the process of fast fission the drift of mass distribution increases rapidly and reaches equilibrium which comes from the effect of driving force.

**Abstract:**

Using our approximate angular momentum projection method with one parameter, the projection spectra of the axially symmetric Hartree-Fock intrinsic states are studied. The approximate and the exact projection matrix elements are obtained and compared each other. The projection integrals for angular momentum J=1 to 11 are given. The energy spectra of the nuclei

^{44}Ti and

^{50}Ti are calculated, and the results coincide with the observed energy levels fairly well.

**Abstract:**

In this paper, a controlled annihilation principle of particles and antiparticles is suggested. The particles and antiparticles are kept in a common space by an electromagnetic field to form an equipartisma or semiequipartisma. The equipartisma and simiequipartisma are new meaterial form, they can annihilate themselves and liberate their energy at usual temperature. One may control the annihilation life-time and energy liberated speed with adjustment of the particle and antiparticle density.

**Abstract:**

A simple relaxation equation have been obtained from the master equation of the occupation number by means of the time average approximation in the dissipation diabatic dynamic theory. Contributions from one-body and two-body collision processes to the rate of occupation number have been compared quantitatively.

**Abstract:**

The cosmological term is necessaritly vanishing in a conformal gravitational theory, and the sum of the induced cosmological constants of all the brocken gauge symmetries cancels the curvature of the background spacetime. Thus the sum of all the cosmological constants is vanishing when the background spacetime is Minkowskian. Furthermore, the spontaneous breaking of a gauge symmetry through the Higgs mechanism is always accompanied by a phase transition of the background spacetime.

**Abstract:**

A detailed analysis of the particle-particle correlation has been made and modes of internal motions have been found.

**Abstract:**

Calculations have been performed for the energy separation of the two major substitutional states of the hypernucleus

^{40Λ}Ca. The (K

^{－},π

^{－}) cross sections are calculated in the framework of the distorted-wave impulse approximation. Information about the ΛN interaction is then extracted, particularly, on the effects of the strength parameters on cross sections. The result shows that the ΛN interaction adopted previously for the 1p shell hypernuclei might be suitable to use for the (K

^{－},π

^{－}) reaction in which medium heavy hypernucleus

^{40Λ}Ca are produced, but the value for the strength parameter of the central potential has to be changed from 0.99 to 0.78.

**Abstract:**

The rephasing invariant formulation for the K

^{0}-K

^{0}system is given and used to discuss the signs of the B parameter in M

_{12}calculation andsin δ in the K-M matrix (both are positive). The meaning of the singularity appeared in the exact formula of the ε parameter, which does not appear in the popular formula in the literature, is also discussed.

**Abstract:**

The combination of partition temperature with Bose-Einstein statistics is generalized to describe the proton nucleus collision. The rapidity distribution of pp, p-Ar and p-Xe at P_{L}=200GeV/c have been calculated and compared with experiment. The interesting possibility of observing pion condensation in p-A collision is investigated.

**ISSN** 1674-1137 **CN** 11-5641/O4

Original research articles, Ietters and reviews Covering theory and experiments in the fieids of

- Particle physics
- Nuclear physics
- Particle and nuclear astrophysics
- Cosmology

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